New York on Tuesday joined six other states in suing the federal Environmental Protection Agency for violating the Clean Air Act by failing to limit air pollution emissions from outdoor wood-heaters.

New York Attorney General Eric Schneiderman said the lawsuit claims that the existing 25-year-old EPA emission limits are outdated, not being enforced and leave out many types of outdoor residential wood-heaters.

In 2010, the state Department of Environmental Conservation ordered that all new outdoor wood-heaters cut emissions by 90 percent. But EPA has not followed suit.

"EPA's regulations simply haven't kept pace with the proliferation of wood-burning devices or the availability of cleaner-burning units. Smoke from residential wood-burning heaters poses a serious health threat, especially in New York's rural communities," Schneiderman said in a statement.

Wood smoke contains pollutants that are linked to public health impacts such as asthma attacks, heart attacks, and premature death, a study by the Attorney General's Office found in 2008.

Schneiderman's office estimated there were 14,500 outdoor wood boilers sold in New York between 1999 and 2007.

Recent EPA data found that soot from the wood-heaters accounts for 13 percent of all soot pollution in the country.

In 1988, the EPA found that pollutants in wood smoke endanger public health and that residential wood-heaters must be regulated by the Clean Air Act's New Source Performance Standards. That same year, the EPA exempted heating devices from those emission standards, including wood-heaters.

Under the Clean Air Act requirements, the EPA should have to enforce the pollution emission limits for wood-heaters and review and revise the limits at least every eight years. Since 1988, three eight-year mandated reviews have not been completed by the EPA, the lawsuit said.

There was no immediate comment from the EPA, which is closed due to the federal government shutdown.

Connecticut, Maryland, Massachusetts, Oregon, Rhode Island, Vermont, and the Puget Sound Clean Air Agency joined the lawsuit, which was filed in Washington, D.C.